Ignition arrangements for internal combustion engines

ABSTRACT

The ignition capacitor is connected to a DC to AC converter to be charged, and then discharged in synchronism with the desired firing of the spark plugs. The ignition capacitor is discharged by rendering conductive a thyristor, which has a de-ionization period. During discharge and immediately thereafter, a timer, consisting of a multivibrator, and an auxiliary switch prevent the DC to AC converter from charging for a period at least equal to the discharge period of the thyristor The auxiliary switch can be a transistor that open circuits the conductive path to the control winding of the converter or a thyristor connected in series or in shunt with the secondary winding of the converter.

United States Patent Issler et a1.

[54] IGNITION ARRANGEMENTS FOR INTERNAL COMBUSTION ENGINES [72]Inventors: Jiirg Issler; Helmut Roth, both of Stuttgart; GerhardSiihner, Geradstetten, all of Germany [73] Assignee: Robert BoschGmbI-I, Stuttgart, Germany [22] Filed: Sept. 22, 1970 [21] Appl. No.:74,351

[30] Foreign Application Priority Data Oct. 18, 1969 Germany ..P 19 52603.5

[52] US. Cl. ..123/148 E, 315/209 [51] Int. Cl ..F02p H00 [58] Field ofSearch ..123/148 E; 315/209 [56] References Cited UNITED STATES PATENTS3,546,528 12/1970 Fisher ..123/148E 1 Sept. 19, 1972 3,489,129 1/1970Issler et a1. ..123/148 E 3,487,822 1/1970 Hufton et a1. 123/148 E3,473,061 10/1969 Soehner et a1 ..123/148 E X Primary Examiner-LaurenceM. Goodridge AttorneyMichael S. Striker [5 7 ABSTRACT The ignitioncapacitor is connected to a DC to AC converter to be charged, and thendischarged in synchronism with the desired firing of the spark plugs.The ignition capacitor is discharged by rendering conductive athyristor, which has a de-ionization period. During discharge andimmediately thereafter, a timer, consisting of a multivibrator, and anauxiliary switch prevent the DC to AC converter from charging for aperiod at least equal to the discharge period of the thyristor Theauxiliary switch can be a transistor that open circuits the conductivepath to the control winding of the converter or a thyristor connected inseries or in shunt with the secondary winding of the converter.

27 Claims, 3 Drawing Figures AAL AAA

PATENTED SE? 1 9 m2 SHEET 2 OF 2 m WUE Mex Arrow [y IGNITIONARRANGEMENTS FOR INTERNAL COMBUSTION ENGINES BACKGROUND OF THE INVENTIONcharging the ignition capacitor, such as a DC to AC converter, the highvoltage output of the converter being connected to the ignitioncapacitor. The ignition capacitor is connected to discharge through thesecondary winding of the spark coil when a pulse operated, normallynon-conductive, electronic switch, such as a thyristor, is madeconductive in synchronism with the operation of the engine. The sparkcoil secondary is connected to one or more spark plugs to fire thelatter, and a pulse generator, operating in dependence on the engine,controls the electronic switch.

The sudden discharging of the ignition capacitor causes a voltage pulsewith a steep wave front, so that even badly fouled spark plugs produce ahot spark.

With these known ignition arrangements, the means for charging theignition capacitor, such as the DC to AC converter, continually chargesthe ignition capacitor, even when the latter is discharging. It has beenobserved that the de-ionization of the electronic switch for dischargingthe ignition capacitor is prevented, the electronic switch, which iscommonly a thyristor, remaining continuously conductive and therebypreventing the generation of ignition pulses for the spark plugs.

SUMMARY OF THE INVENTION An object of the invention is an arrangementfor insuring de-ionization of the electronic switch for discharging theignition capacitor.

The invention consists essentially of ignition capacitor means adaptedto be charged and then discharged so as to produce an ignition causingspark, means for charging the ignition capacitor means, pulse operated,normally non-conductive, electronic switch means in circuit with theignition capacitor means to permit discharge of the latter whenconductive, said electronic switch means having a de-ionization period,pulse generator means for generating pulses in dependence on engineoperation to render the electronic switch means conductive, andauxiliary switch means controlled by the pulses for preventing chargingof the ignition capacitor means for at least the duration of thedeionization period of the electronic switch means, whereby the lattercan become non-conductive in the interval between the pulses.

The novel features which are considered as characteristic for theinvention are set forth in particular in the appended claims. Theinvention itself, however, both as to its construction and its method ofoperation, together with additional objects and advantages thereof, willbe best understood from the following description of specificembodiments when read in con nection with the, accompanying drawing.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a circuit diagram showingone embodiment of the invention; and

FIGS. 2 and 3 are circuit diagrams showing two further embodiments ofthe invention.

DESCRIPTION OF THE PREFERRED EMBODIMENTS With reference to FIG. 1, anoperating switch 11 connects the ignition arrangement to a directcurrent source 12, which can be, for example, the battery of a motorvehicle driven by an internal combustion engine, not shown. When theswitch 11 is closed, the current source 12 is shunted by a Zener diode13, which is connected to be normally non-conductive. A capacitor 14,which bypasses interference pulses conducted to the ignitionarrangement, also shunts the current source 12.

The ignition arrangement comprises a DC to AC converter 15, which has alow voltage input with terminals 16 and 17, the converter beingconnected to the current source 12 when the switch 11 is closed. Apositive line 18 connects the input terminal 16 to the positive pole ofthe source 12, and a negative, or ground, line 19 connects the inputterminal 17 to the negative pole of the source. The high voltage outputof the converter has terminals 20 and 21, the terminal 20 beingconnected by a lead 24 to one plate of an ignition capacitor 22. Theother plate of the ignition capacitor is connected by the primarywinding 25 of the spark coil 26 and by the ground line 19 to the otheroutput terminal 21. The cathode of a charging diode 23 is connected tothe output terminal 20. The secondary winding 27 of the spark coil isconnected to at least one spark plug 28. In accordance with theinvention, there can be provided, in a known manner, an ignitiondistributor for connecting the secondary 27 to successive spark plugs ofa series.

Connected between the lead 24 and the ground line 19 is the switchingpath A-K of a controllable electronic discharge switch 29, whichpreferably is a thyristor, the anode A being connected to the lead 24and the cathode K to the ground line 19. A pulse generator isoperatively connected to the control electrode lead of the dischargingswitch 29. The pulse generator operates in dependence on the operationof the internal combustion engine, and produces a triggering pulsewhenever a spark plug 28 is to be sparked, which triggering pulserenders the switching path A-K of the switch 29 conductive.

By way of example, the pulse generator 30 can operate photoelectricallyor electromagnetically. In the present embodiment, however, the pulsegenerator 30 comprises a conventional circuit interruptor 31, which isoperated by a cam 32 driven by the internal combustion engine. With asuitable control circuit, this form of the pulse generator isparticularly suited to the ignition arrangement of the invention. Thiscontrol circuit has a control capacitor 33 and a control resistor 34connected in series, the capacitor end 35 being connected to the groundline 19 and the resistor end 36 being connected by way of an emittercollector path 37, 38 of a PNP input transistor 39 to the positive line18. The common junction 40 between the control capacitor and controlresistor is connected by the emitter collector path 41-42 of a PNPcontrol transistor 43 to the control electrode S of the dischargingswitch 29. The base 44 of the control transistor is connected by atleast one diode 45 to the resistor end 36 of the series connectedcontrol capacitor and control resistor. The polarity of the diode 45permits current to flow only in a conductive direction for the controltransistor 43. A resistor 47 connects the base 46 of the inputtransistor 39 to the positive line 18, and a resistor 48 connects thebase 46 to the ground line 19 by way of the circuit interruptor 31. Theresistor 47 is shunted by a non-conductively connected diode forprotecting the base emitter path 46-37 of the input transistor 39 fromexcessive voltage. The capacitor 50 s also shunting the resistor 47prevents interference pulses from reaching the base emitter path 46-37.A capacitor 51 shunts the base emitter path 44-41 of the controltransistor 43 to prevent interference pulses from reaching this controlpath. Interference pulses are prevented from reaching the control pathS-K of the discharging switch 29 by capacitor 52 shunted across thispath. The control electrode S of the discharging switch 29 is connectedto the common junction between two series connected resistors 55 and 56that are connected between the ground line 19 and the collector 42 ofthe control transistor 43. The anode A of the discharge switch 29 isconnected to the ground line 19 by a series connected capacitor 57 andresistor 58. The anode A is also connected by a resistor 59 to thecathode of a diode 60 the anode of which is connected to the junction40. A resistor 61, which simplifies the setting of the voltage, isshunted across the series connected control capacitor 33 and controlresistor 34. A resistor 62 is connected between the positive line 18 andthe junction 63 to which the resistor 48 is connected. The Zener diode Zshunted across the control capacitor 33 limits the voltage to which thelatter can be charged.

The DC to AC converter can be of known design, having either a singleended or push-pull output. In the preferred embodiment, shown in FIG. 1,the converter has a single ended output. The input of the converter 15has a primary winding 64 and a control winding 65, and the output has asecondary winding 66, all of these windings being wound on a common ironcore 67. The primary winding 64 together with the emitter collector path68-69 of the NPN switching transistor 70 forms a series circuit, one endof which is connected to the input terminal 16 and the other end ofwhich is connected to the input terminal 17. A lead 72 connects the base71 of the switching transistor 70 to one end of the control winding 65,the other end of which latter is connected to the common junction 73 oftwo series connected resistors 74 and 75, which form a voltage dividerbetween the positive line 18 and the ground line 19. A non-conductivelyconnected diode 76 connects the base 71 to the ground line 19. Aparallel connected capacitor 77 and a Zener diode 78 are shunted acrossthe emitter collector path 68-69 to protect the latter against excessivevoltage. One end of the secondary winding 66 of the converter 15 isconnected to the anode of the diode 23, and the other end is connectedto the terminal 21 in the ground line 19.

The ignition arrangement thus far described operates in the followingmanner. When the operating switch 11 is closed, the DC to AC converter15 begins to oscillate. Assuming, first of all, that the lead 72connects the base 71 of the switching transistor 70 directly to thecontrol winding 65, the converter 15 oscillates continuously as long asthe operating switch 11 is closed. It being presumed that the operationof the converter 15 is known, it will simply be remarked that thefrequency of the high voltage induced in the secondary winding 66 isappreciably higher than the frequency at which the spark plugs 28 aresparked. The charging diode 23 insures that only the positive half wavesof the AC high voltage are used, so that the plate of the ignitioncapacitor 22 connected to the lead 24 receives a positive potential andthe plates connected to the ground line 19 are at negative potential.

At the moment that a spark plug 28 is supposed to spark, the cam 32opens the circuit interrupter 31, causing a positive potential to appearat the base 46 of the input transistor 39, thereby renderingnon-conductive the emitter collector path 37-38 of this transistor. Thecontrol capacitor 33, which has been previously charged while theemitter collector path 37-38 was conductive, can now discharge, wherebya current flows from the upper plate of the capacitor 33 throughresistors 34 and 61 to the ground line 19. The resulting voltage dropacross the resistor 34 causes at the base 44 of the control transistor43 a negative voltage that turns on the emitter collector path 41-42, sothat the control capacitor 33 can now also discharge through thisemitter collector path and the two resistors 55 and 56 connected inseries. The resulting voltage at the junction 53 of these two resistorsconstitutes for the control electrode S of the discharge switch 29 atriggering pulse that turns on the anode cathode path A-K. The ignitioncapacitor 22 is now free to discharge through this anode cathode pathand the primary winding 25 of the spark coil 26, thereby inducing in thesecondary winding 27 a high voltage pulse that causes the plug 28 toproduce an ignition spark.

Once the anode cathode path A-K of the discharge switch 29 isconductive, there is provided for the control capacitor 33 a furtherdischarge path that runs through the diode 60 and the resistor 59. Thisadditional discharge path accelerates the discharge of the controlcapacitor 33. The junction 40 is then held at such a potential duringthe sparking procedure that there are no disturbing effects should thecircuit interruptor 31 momentarily close while it is opening.

The series connected capacitor 57 and resistor 58 conduct the negativehalfwaves, which appear while the ignition capacitor 22 is discharging,to the anode A of the discharge switch 29, thereby encouragingdeionization of the anode cathode path A-K.

After the sparking procedure is over, the circuit interrupter 31 isagain closed, and energy is again stored in the control capacitor 33 forstarting the next sparking procedure. Contact chatter of the circuitinterruptor 31, causing the latter momentarily to reopen while closing,cannot cause the plug 28 to spark, because the control capacitor 33 hasstored too little energy to produce a trigger pulse of sufficient peakamplitude to turn on the thyristor 29.

Even though a conventional circuit interrupter 31 is used, the describedcircuit insures that an effective trigger pulse is produced only when aspark is desired.

With the described ignition arrangement, the ignition capacitor 22 isalso charged during the sparking procedure. Consequently, it may occurat very high firing frequencies that the anode cathode path A-K of thedischarge switch 29 does not de-ionize and thus remains continuouslyconductive. Therefore, no ignition sparks are produced. To avoid this,the trigger pulse used to turn on the switching path A-K of thedischarge switch 29 is also used to operate an electrically controlledauxiliary switch 79, which prevents the DC to AC converter from chargingthe ignition capacitor 22 at least for the de-ionization period of thethyristor 29.

The period of time that the trigger pulse switches the switching path ofthe auxiliary switch 79 is precisely determined by an electric timer 80,which is connected in the control connection 81 leading from the controlelectrode S of the discharge switch 29 to the auxiliary switch 79. Theelectric timer can be, for example, an RC circuit or a time dependentdifferentiator. It can also be a Schmitt trigger, which as long as thetrigger pulse at the control electrode S of the discharge switch 29exceeds a predetermined level, switches the auxiliary switch 79.Particularly suitable is a monostable mul tivibrator, shown in FIG. 1.The monostable multivibrator comprises an npn input transistor 82 and anNPN output transistor 83. The emitter 84 of the input transistor 82 isconnected to the ground line 19; the collector 85 is connected by aresistor 86 and also bya series connected feedback capacitor 87 and aresistor 88 to the positive line 18; and the base 89 is connected by acontrol connection 81 -composed of a resistor 90 and a diode 91, whichconducts only positive control pulses to the junction between the tworesistors 55 and 56 and thus to the control electrode S of the dischargeswitch 29. The emitter 92 of the output transistor 83 is connected by anemitter resistor 93 to the ground line 19; the base 94 is connected tothe junction 95 between the feedback capacitor 87 and the resistor 88;and the collector 96 is connected by a resistor 97 to the positive line18 and by a feedback resistor 98 to the base 89 of the input transistor82.

The auxiliary switch 79 can be, for example, an electromagnetic relay ora semiconductor component. The auxiliary switch can be connected eitherin the-low voltage input or in the high voltage output of the DC to ACconverter 15. In the preferred embodiment, shown in FIG. 1, theauxiliary switch 79 is an NPN transistor 99, of which the emittercollector path 100-101 forms the switching path. This switching pathlies in the connection 72 between the base 71 of the switchingtransistor 70 and the control winding 65, the emitter 100 of thetransistor 99 being connected to the base 71 of the switching transistor70 and the collector 101 being connected to the control winding 65. Theemitter collector path 100-101 is protected in a known manner by a diode102. The base 103 of the transistor 99 is connected to the emitter 92 ofthe output transistor 83 of the multivibrator.

If, when an ignition spark is to be produced, a trigger pulse appears atthe control electrode S of the discharge switch 29, this pulse isconducted through the diode 91 and the resistor 90 to the base 89 of themultivibrator input transistor 82, thereby triggering the multivibratorto its unstable state. In this state the emitter collector path 84-85 ofthe input transistor 82 is conductive, whereas the emitter collectorpath 92-96 of the output transistor 83 is non-conductive. While themultivibrator is in its unstable state the base 103 of transistor 99therefore is not biassed, so that the emitter collector path 100-101 isn0n-conductive; and the control winding 65 of the converter 15 is notenergized. Therefore, the converter 15 cannot charge the ignitioncapacitor 22 while the multivibrator is in its unstable state. Thecharging time constant of the feedback capacitor 87 is chosen to beequal or somewhat longer than the de-ionization time of the particularkind of electronic discharge switch 29 used.

If the DC to AC converter has push-pull output, there being, as is wellknown, two control windings, two primary windings, and two switchingtransistors, the described action is obtained if the transistor thatcomposes the auxiliarly switch is so connected to one of the two controlwindings and to one of the two switching transistors as shown in FIG. 1.

With reference to FIG. 2, the ignition arrangement shown differs fromthat shown in FIG. 1 in that the auxiliary switch 79 is composed by athyristor 104 connected in the high voltage output of the converter 15.The anode cathode path A-A' of the thyristor 104 is connected in serieswith the secondary winding 66, the anode A being connected to the groundline 19 and the cathode K to the secondary 66. The cathode K is alsoconnected to the ground line 19 by a lead 105 having at least one diode106 of which the cathode is connected to the line 19. The controlelectrode S of the thyristor 104 is connected to the emitter 92 of theoutput transistor 83 of the monostable multivibrator. In thisembodiment, the lead 72 is connected directly between the base 71 of theswitching transistor 70 and the control winding 75. Aside from heforegoing, the embodiment shown in FIG. 2 is exactly the same as thatshown in FIG. 1. Therefore, the circuit of FIG. 2 is shown and describedonly insofar as it differs in design and operation from that of FIG. 1.All components having the same function are denoted by the samereference numerals.

The circuit shown in FIG. 2 operates in the following manner. Theemitter collector path 92-96 of the multivibrator output transistor 83is normally conductive during operation. The resulting voltage dropacross the emitter resistor 93 insures that the control electrode S ofthe thyristor 104 is biassed positive with respect to the cathode K.Each of the positive charging pulses produced by the converter 15 isconducted by the auxiliary switch 79 to the ignition capacitor 22. Assoon as a trigger pulse appears at the control electrode S of thedischarge switch 29 and the monostable multivibrator is triggered to itsunstable state, the emitter collector path 92-96 of the outputtransistor 83 is rendered nonconductive, and the positive bias acrossthe emitter resistor 93 is no longer present, so that the auxiliaryswitch 79, formed by the thyristor 104, is non-conductive while themultivibrator is in its unstable state. Consequently, as long as themultivibrator is in its unstable state the ignition capacitor 22 is notcharged, therefore preventing any hindrance of de-ionization of thedischarge switch 29. The diode 106 insures that no charging pulses canbe conductive through the lead extending from the cathode A to theground line 19.

The ignition arrangement shown in FIG. 3 also differs from that shown inFIG. 1 in that the auxiliary switch 79 is composed of a thyristor 107,which is connected in the high voltage output of the converter 15.

In this embodiment, the anode cathode path A-K", which is the switchingpath, is shunted across the secondary winding 66 of the converter 15,the anode cathode path A"-K" preferably being connected in series with aresistor108. The cathode K" of the thyristor 107 is connected to theground line 19, the anode A is connected by a resistor 108 with theanode of the charging diode 23, and the control electrode S" isconnected to the collector 110 of a PNP transistor 11 1 and by aresistor 109 to the ground line 19. The emitter 1 12 of the transistor111 is connected by a resistor 113 to the positive line 18, and the base114 to the emitter 92 of the multivibrator output transistor 83. Thelead 72 connects the base 71 of the switching transistor 70 directly tothe control winding 65.

Aside from the foregoing, the circuit is the same as that shown inFIG. 1. For this reason, the circuit is shown and described only insofaras it differs in design and operation from the circuit shown in FIG. 1.Components having the same function are denoted by the same referencenumerals.

The embodiment shown in FIG. 3 operates in the following manner. As intheprevious embodiment, the emitter collector path 92-96 of themultivibrator output transistor 83 is conductive during operation. Theemitter collector path 92-96 insures that the base 114 of transistor 111is held at the same potential as the emitter 112. Consequently, theemitter collector path 112-1 of transistor 1 1 l is nonconductive.Therefore, the control electrode S of the thyristor 107 is notpositively biassed, and the anode cathode path A"-K" is non-conductive.The positive charging pulses from the converter 15 are free to chargethe ignition capacitor 22..As soon as the trigger pulse appears at thecontrol electrode S of the discharge switch 29 and the monostablemultivibrator is triggered to its unstable state, the emitter collectorpath 92-96 of the output transistor 83 becoming non-conductive, the base114 of transistor 111 is negatively biassed, so that theemitter'collector path 112-110 is rendered conductive, and a positivevoltage appears at the control electrode S" of the thyristor 107.Consequently, the anode cathode path A"-K". becomes conductive, wherebyfor the duration of the unstable state of the multivibrator all voltagesappearing across the secondary winding 66 are at least partly shortcircuited by the resistor 108 and the conductive switching A-K", therebypreventing effective charging of the ignition capacitor 22.

It will be understood that each of the elements described above, or twoor more together, may also find a useful application in other types ofcircuits differing from the types described above.

While the invention has been illustrated and described as embodied inignition arrangements for internal combustion engines, it is notintended to be limited to the details shown, since various modificationsand structural changes may be made without departing in any way from thespirit of the present invention.

Without further analysis, the foregoing will so fully reveal the gist ofthe present invention that others can by applying current knowledgereadily adapt it for various applications without omitting featuresthat, from the standpoint of prior art, fairly constitute essentialcharacteristics of the generic or specific aspects of this inventionand, therefore, such adaptations should and are intended to becomprehended within the meaning and range of eq uivalence of thefollowing claims.

What is claimed as new and desired to be protected by Letters Patent isset forth in the appended claims. We claim:

1. In an ignition system for an internal combustion engine, incombination, spark plug means; ignition capacitor means adapted to becharged and then discharged so as to produce a single spark at saidspark plug means for igniting a combustible mixture with said singlespark; oscillator means connected to said capacitor means for applyingcharging pulses to said capacitor means; pulse-operated, normallynon-conductive electronic switch means in circuit with said ignitioncapacitor means and operative to permit discharge of the latter whensaid electronic switch means is in conductive state, said electronicswitch means having a deionization period; pulse generator means coupledto said engine and connected with said electronic switch means forgenerating control pulses and applying such pulses individually to saidelectronic switch means and each for the duration of a first timeinterval for thereby rendering said electronic switch means conductive,the frequency of generation of said control pulses being dependent onthe operation of said engine; and auxiliary switch means connected withsaid oscillator means and with said pulse generator means and includingelectric timer means controlled by the respective control pulse forpreventing charging of said ignition capacitor means for the duration ofa second time interval subsequent to said first time intervalindependent of the timing of the discharge of said capacitor and atleast equalling the de-ionization period of said electronic switchmeans, the frequency of generation of said control pulses correspondingto the frequency of sparks produced at said spark plug means, and thefrequency of said charging pulses being substantially higher than thefrequency of said control pulses and of said sparks.

2. An arrangement as defined in claim 1, wherein said timer means is amonostable multivibrator.

3. An arrangement as defined in claim 1, wherein said electronic switchmeans has a control electrode, said control electrode being connected tooperate said auxiliary switch means.

4. An arrangement as defined in claim 3 wherein said electronic switchmeans is a thyristor and said pulse generator means is an engineoperated circuit interrupter.

5. An arrangement as defined in claim 4, further including a directcurrent source; series connected control resistor and control capacitor,wherein said control capacitor and the cathode of said thyristor areconnected to the negative pole of said direct current source; an inputtransistor of which the emitter collector path is connected between saidcontrol resistor and the positive pole of said DC source; a controltransistor of which the emitter collector path is connected between thejunction between said control resistor and capacitor and the controlelectrode of said thyristor; at least one diode connectednon-conductively between the base of said control transistor and thejunction between said control resistor and said emitter collector pathof said input transistor; at least one first resistor connecting thebase of said input transistor to the positive pole of said directcurrent source; and at least one second resistor connected in serieswith said circuit interrupter, said second resistor and said circuitinterrupter being connected between the base of said input transistorand the negative pole of said direct current source.

6. An arrangement as defined in claim 5, including a voltage settingresistor shunted across said series connected control resistor andcapacitor.

7. An arrangement as defined in claim 5, including two series connectedresistors connected between the collector of said control transistor andthe cathode of said thyristor, and the common junction between said twoseries connected resistors being connected to said thyristor controlelectrode.

8. An arrangement as defined in claim 5, including at least one firstdiode connected between the anode of said thyristor and the commonjunction between said series connected control resistor and capacitor,the cathode of said first diode being connected to said thyristor anode.

9. An arrangement as defined in claim 8, including a resistor connectedin series with said first diode.

10. An arrangement as defined in claim 8, including series connectedcapacitor and resistor shunted across the anode cathode path of saidthyristor.

11. An arrangement as defined in claim 1, wherein said means forcharging is a DC to AC converter having an input and an output, saidinput comprising at least one primary winding and at least one controlwinding and said output having a secondary winding; a common core forsaid windings; a switching transistor of which the emitter collectorpath is connected in series with said primary winding across said directcurrent; means connecting the base of said switching transistor to saidcontrol winding; and a charging diode connecting said secondary windingto said ignition capacitor means to form for the latter a chargingcurrent path composed of said secondary winding, charging diode, andignition capacitor means.

12. An arrangement as defined in claim 11, including a diodenon-conductively connecting the base of said switching transistor to onepole of said direct current source; two series connected resistorsconnected across said direct current source, said control winding beingconnected to the common junction between said two series connectedresistors, whereby the base of said switching transistor is connectedthrough said control winding to said common junction.

13. An arrangement as defined in claim 11, wherein said input and outputare respectively low and high voltage, and said auxiliary switchingmeans comprises a switching path, said switching path being connected insaid input.

14. An arrangement as defined in claim 11, wherein said auxiliaryswitching means comprises a switching path, and said switching path andsaid secondary winding are connected in series.

15. An arrangement as defined in claim 11, wherein said auxiliaryswitching means comprises a switching path, and said switching path isconnected in shunt with said secondary winding.

16. An arrangement as defined in claim 15, including a resistorconnected in series with said switching path, said series connectedresistor and switching path being shunted across said secondary winding.

17. An arrangement as defined in claim 2, wherein said electronic switchmeans has a control electrode, said control electrode being connected tooperate said auxiliary switch means; and further including a directcurrent source; an input and an output transistor comprised by saidmultivibrator, the emitter of said input transistor being connected toone pole of said direct current source; a resistor connecting thecollector of said input transistor to the other pole of said directcurrent source; a feedback capacitor connecting the collector of saidinput transistor to the base of said output transistor; a resistorconnecting the base of said output transistor to said other pole of saiddirect current source; a feedback resistor connecting the base of saidinput transistor to the collector of said output transistor; an emitterresistor connecting the emitter of said output transistor to said onepole of said direct current source, the collector of said outputtransistor being connected to said other pole of said direct currentsource.

18. An arrangement as defined in claim 17, including a resistorconnected between the collector of said output transistor and said otherpole.

19. An arrangement as defined in claim 17, wherein said input and outputtransistors are both NPN type, the collector and emitter of both saidtransistors being respectively connected to the positive and negativepoles of said direct current source.

20. An arrangement as defined in claim 13, wherein said auxiliary switchmeans is a transistor of which the emitter collector path forms aswitching path.

21. An arrangement as defined in claim 13, wherein said auxiliary switchmeans comprises a switching path, said switching path being connectedbetween the base of said switching transistor and said control winding.

22. An arrangement as defined in claim 14, wherein said auxiliary switchmeans is a thyristor and the cathode anode path thereof comprises saidswitching path.

23. In an ignition system for an internal combustion engine, incombination, ignition capacitor means adapted to be charged and then tobe discharged so as to produce an ignition causing spark; means forcharging said ignition capacitor means; pulse operated, normallynon-conductive, electronic switch means in circuit with said ignitioncapacitor means to permit discharge of the latter when conductive, saidelectronic switch means having a de-ionization period; pulse generatormeans for control pulses in dependence on engine operation to rendersaid electronic switch means conductive; auxiliary switch meanscontrolled by said control pulses for preventing charging of saidignition capacitor means for at least the duration of said de-ionizationperiod of said electronic switch means, whereby the latter can becomenon-conductive in the intervals between said control pulses; electricaltiming means for determining the duration during which said auxiliaryswitch means prevents charging of said ignition capacitor means, saidtiming means being a monostable multivibrator, said electronic switchmeans having a control electrode, said control electrode being connectedto operate said auxiliary switch means; a direct current source; aninput and an output transistor comprised by said multivibrator, theemitter of said input transistor being connected to one pole of saiddirect current source; a resistor connecting the 1 1 collector of saidinput transistor to the other pole of said direct current source; afeedback capacitor connecting the collector of said input transistor tothe base of said output transistor; a resistor connecting the base ofsaid output transistor to said other pole of said direct current source;a feedback resistor connecting the base of said input transistor to thecollector of said output transistor; an emitter resistor connecting theemitter of said output transistor to said one pole of said directcurrent source, the collector of said output transistor being connectedto said other pole of said direct current source, said electronic switchmeans being a thyristor and said pulse generator means being an engineoperated circuit interrupter; series connected control resistor andcontrol capacitor, wherein said control capacitor and the cathode ofsaid thyristor are connected to the negative pole of said direct currentsource; a further input transistor of which the emitter collector pathis connected between said control resistor and the positive pole of saiddirect current source; a control transistor of which the emittercollector path is connected between the junction between said controlresistor and capacitor and the control electrode of said thyristor; atleast one diode connected non-conductively between the base of thecontrol transistor and the junction between said control resistor andsaid emitter collector path of said further input transistor; at leastone first resistor connecting the base of said input transistor to thepositive pole of said direct current source; at least one secondresistor connected in series with said circuit interrupter, said secondresistor and said circuit interrupter being connected between the baseof said further input transistor and the negative pole of said directcurrent source; a diode connecting said thyristor control electrode tothe base of said multivibrator input transistor to conduct only positivepulses to said base.

24. In an ignition system for an internal combustion engine, incombination, ignition capacitor means adapted to be charged and then tobe discharged so as to produce an ignition causing spark; means forcharging said ignition capacitor means; pulse operated, nor mallynon-conductive, electronic switch means in circuit with said ignitioncapacitor means to permit discharge of the latter when conductive, saidelectronic switch means having a deionization period; pulse generatormeans for generating pulses in dependence on engine operation to rendersaid electronic switch means conductive; auxiliary switch meanscontrolled by said single control pulse for preventing charging of saidignition capacitor means for at least the duration of said de-ionizationperiod of said electronic switch means, whereby the latter can becomenon-conductive in the intervals between said control pulses; electricaltiming means for determining the duration during which said auxiliaryswitch means prevents charging of said ignition capacitor means, saidtiming means being a mono-stable multivibrator, said electronic switchmeans having a control electrode, said control electrode being connectedto operate said auxiliary switch means; a direct current source; aninput and an output transistor comprised by said multivibrator, theemitter of said input transistor being connected to one pole of saiddirect current source; a resistor connecting the collector of said inputtransistor to the other pole of said direct current source; a feedbackcapacitor connecting the collector of said input transistor to the baseof said output transistor; a resistor connecting the base of said outputtransistor to said other pole of said direct current source; a feedbackresistor connecting the base of said input transistor to the collectorof said output transistor; an emitter resistor connecting the emitter ofsaid output transistor to said one pole of said direct current source,the collector of said output transistor being connected to said otherpole of 'said direct current source, said input and output transistorsbeing both npn type, the collector and the emitter of both saidtransistors being respectively connected to the positive and negativepoles of said direct current source, said means for charging being a DCto AC converter having a low voltage input and a high voltage output,said input comprising at least one primary winding and at least onecontrol winding and said output having a secondary winding, and whereinsaid auxiliary switch means comprises a switching path, said switchingpath being connected in said input; and further including a common corefor said winding; a switching transistor of which the emitter collectorpath is connected in series with said primary winding across said directcurrent source; means connecting the base of said switching transistorto said control winding; a charging diode connecting said secondarywinding to said ignition capacitor means to form for the latter acharging current path composed of said secondary winding, chargingdiode, and ignition capacitor means; a diode nonconductively connectingthe base of said switching transistor to one pole of said direct currentsource; two series connected resistors connected-across said directcurrent source, said control winding means connected to the commonjunction between said two series connected resistors, whereby the baseof said switching transistor is connected through said control windingto said common junction, and wherein said auxiliary switch means is anNPN transistor of which the collector is connected to said controlwinding, the emitter to the base of said switching transistor, and thebase to the output transistor of said multivibrator.

25. in an ignition system for an internal combustion engine, incombination, ignition capacitor means adapted to be charged and then tobe discharged so as to produce an ignition causing spark; means forcharging said ignition capacitor means; pulse operated, normallynon-conductive, electronic switch means in circuit with said ignitioncapacitor means to permit discharge of the latter when conductive, saidelectronic switch means having a de-ionization period; pulse generatormeans for generating pulses in dependence on engine operation to rendersaid electronic switch means conductive; auxiliary switch meanscontrolled by said pulses for preventing charging of said ignitioncapacitor means for at least the duration of said deionization period ofsaid electronic switch means, whereby the latter can becomenon-conductive in the intervals between said pulses, said means forcharging being a DC to AC converter having an input and an output, saidinput comprising at least one primary winding and at least one controlwinding and said output having a secondary winding; a common core forsaid winding; a switching transistor of which the emitter collector pathis connected in series with said primary winding across said directcurrent source; means connecting the base of said switching transistorto said control winding; a charging diode connecting said secondarywinding to said ignition capacitor means to form for the latter acharging current path composed of said secondary winding, chargingdiodes and ignition capacitor means, said auxiliary switching meanscomprising a switching path, and said switching path and said secondarywinding being connected in series, said auxiliary switching means beinga thyristor and the cathode-anode path thereof comprising said switchingpath; monostable multivibrator timing means for determining the durationduring which said auxiliary switch means prevents charging of saidignition capacitor means, and wherein said electrical switch means has acontrol electrode, said control electrode being connected to operatesaid auxiliary switch means; and further including a direct currentsource; an NPN input and an NPN output transistor comprised by saidmultivibrator, the emitter of said input transistor being connected tothe negative pole of said direct current source; a resistor connectingthe collector of said input transistor to the positive pole of saiddirect current source; a feedback capacitor connecting the collector ofsaid input transistor to the base of said output transistor; a resistorconnecting the base of said output transistor to said positive pole ofsaid direct current source; a feedback resistor connecting the base ofsaid input transistor to the collector of said output transistor; anemitter resistor connecting the emitter of said output transistor to thenegative pole of said direct current source, the collector of saidoutput transistor being connected to the positive pole of said directcurrent source; and wherein the control electrode and the cathode ofsaid thyristor are respectively connected to the emitter of saidmultivibrator output transistor and to said charging diode; a diode ofwhich the anode is connected to the cathode of said thyristor and thecathode is connected to the terminal of said emitter resistor remotefrom the emitter of said multivibrator output transistor.

26. In an ignition system for an internal combustion engine, incombination, ignition capacitor means adapted to be charged and then tobe discharged so as to produce an ignition causing spark; means forcharging said ignition capacitor means; pulse operated, normallynon-conductive, electronic switch means in circuit with said ignitioncapacitor means to permit discharge of the latter when conductive, saidelectronic switch means having a de-ionization period; pulse generatormeans for generating pulses in dependence on engine operation to rendersaid electric switch means conductive; auxiliary switch means controlledby said pulses for preventing charging of said ignition capacitor meansfor at least the duration of said deionization period of said electronicswitch means,

whereby the latter can become non-conductive in the intervals betweensaid pulses, said means for charging being a DC to AC converter havingan input and an output, said output comprising at least one primarywinding and at least one control winding and said output having asecondary winding; a common core for said windings; a switchingtransistor of which the emitter-collector path is connected in serieswith said primary winding across said direct cur rent source; meansconnecting the base of said switching transistor to said controlwinding; a charging diode connecting said secondary winding to saidignition capacitor means to form for the latter a charging current pathcomposed of said secondary winding, charging diode, and ignitioncapacitor means, said auxiliary switching means com prising a switchingpath, and said switching path being connected in shunt with saidsecondary winding; monostable multivibrator timing means for determiningthe duration during which said auxiliary switching means preventscharging of said ignition capacitor means, and wherein said electricalswitch means has a control electrode, said control electrode beingconnected to operate said auxiliary switch means; and further includinga direct current source; an NPN input and an NPN output transistorcomprised by said multivibrator, the emitter of said input transistorbeing connected to the negative pole of said direct current source; aresistor connecting the collector of said input transistor to thepositive pole of said direct current source; a feedback capacitorconnecting the collector of said input transistor to the base of saidoutput transistor; a resistor connecting the base of said outputtransistor to said positive pole of said direct current source; afeedback resistor connecting the base of said input resistor to thecollector of said output transistor; an emitter resistor connecting theemitter of said output transistor to the negative pole of said directcurrent source; the collector of said output transistor being connectedto the positive pole of said direct current source, and wherein saidauxiliary switch means is a thyristor and the cathode anode path thereofcomprises said switching path, one end of said secondary winding beingconnected to the anode of said charging diode, the anode of saidthyristor being connected to said one end of said secondary winding, andthe cathode of said thyristor being connected to the other end of saidsecondary winding; and further including a resistor connecting saidthyristor control electrode to said thyristor cathode; a transistor ofwhich the collector is connected to said thyristor control electrode,the base is connected to the emitter of said multivibrator outputtransistor, and the emitter is connected to the positive pole of saiddirect current source.

27. An arrangement as defined in claim 26, including a resistorconnecting the emitter of said transistor to the positive pole of saiddirect current source.

1. In an ignition system for an internal combustion engine, incombination, spark plug means; ignition capacitor means adapted to becharged and then discharged so as to produce a single spark at saidspark plug means for igniting a combustible mixture with said singlespark; oscillator means connected to said capacitor means for applyingcharging pulses to said capacitor means; pulse-operated, normallynon-conductive electronic switch means in circuit with said ignitioncapacitor means and operative to permit discharge of the latter whensaid electronic switch means is in conductive state, said electronicswitch means having a deionization period; pulse generator means coupledto said engine and connected with said electronic switch means forgenerating control pulses and applying such pulses individually to saidelectronic switch means and each for the duration of a first timeinterval for thereby rendering said electronic switch means conductive,the frequency of generation of said control pulses being dependent onthe operation of said engine; and auxiliary switch means connected withsaid oscillator means and with said pulse generator means and includingelectric timer means controlled by the respective control pulse forpreventing charging of said ignition capacitor means for the duration ofa second time interval subsequent to said first time intervalindependent of the timing of the discharge of said capacitor and atleast equalling the de-ionization period of said electronic switchmeans, the frequency of generation of said control pulses correspondingto the frequency of sparks produced at said spark plug means, and thefrequency of said charging pulses being substantially higher than thefrequency of said control pulses and of said sparks.
 2. An arrangementas defined in claim 1, wherein said timer means is a monostablemultivibrator.
 3. An arrangement as defined in claim 1, wherein saidelectronic switch means has a control electrode, said control electrodebeing connected to operate said auxiliary switch means.
 4. Anarrangement as defined in claim 3, wherein said electronic switch meansis a thyristor and said pulse generator means is an engine operatedcircuit interrupter.
 5. An arrangement as defined in claim 4, furtherincluding a direct current source; series connected control resistor andcontrol capacitor, wherein said control capacitor and the cathode ofsaid thyristor are connected to the negative pole of said direct currentsource; an input transistor of which the emitter collector path isconnected between said control resistoR and the positive pole of said DCsource; a control transistor of which the emitter collector path isconnected between the junction between said control resistor andcapacitor and the control electrode of said thyristor; at least onediode connected non-conductively between the base of said controltransistor and the junction between said control resistor and saidemitter collector path of said input transistor; at least one firstresistor connecting the base of said input transistor to the positivepole of said direct current source; and at least one second resistorconnected in series with said circuit interrupter, said second resistorand said circuit interrupter being connected between the base of saidinput transistor and the negative pole of said direct current source. 6.An arrangement as defined in claim 5, including a voltage settingresistor shunted across said series connected control resistor andcapacitor.
 7. An arrangement as defined in claim 5, including two seriesconnected resistors connected between the collector of said controltransistor and the cathode of said thyristor, and the common junctionbetween said two series connected resistors being connected to saidthyristor control electrode.
 8. An arrangement as defined in claim 5,including at least one first diode connected between the anode of saidthyristor and the common junction between said series connected controlresistor and capacitor, the cathode of said first diode being connectedto said thyristor anode.
 9. An arrangement as defined in claim 8,including a resistor connected in series with said first diode.
 10. Anarrangement as defined in claim 8, including series connected capacitorand resistor shunted across the anode cathode path of said thyristor.11. An arrangement as defined in claim 1, wherein said means forcharging is a DC to AC converter having an input and an output, saidinput comprising at least one primary winding and at least one controlwinding and said output having a secondary winding; a common core forsaid windings; a switching transistor of which the emitter collectorpath is connected in series with said primary winding across said directcurrent; means connecting the base of said switching transistor to saidcontrol winding; and a charging diode connecting said secondary windingto said ignition capacitor means to form for the latter a chargingcurrent path composed of said secondary winding, charging diode, andignition capacitor means.
 12. An arrangement as defined in claim 11,including a diode non-conductively connecting the base of said switchingtransistor to one pole of said direct current source; two seriesconnected resistors connected across said direct current source, saidcontrol winding being connected to the common junction between said twoseries connected resistors, whereby the base of said switchingtransistor is connected through said control winding to said commonjunction.
 13. An arrangement as defined in claim 11, wherein said inputand output are respectively low and high voltage, and said auxiliaryswitching means comprises a switching path, said switching path beingconnected in said input.
 14. An arrangement as defined in claim 11,wherein said auxiliary switching means comprises a switching path, andsaid switching path and said secondary winding are connected in series.15. An arrangement as defined in claim 11, wherein said auxiliaryswitching means comprises a switching path, and said switching path isconnected in shunt with said secondary winding.
 16. An arrangement asdefined in claim 15, including a resistor connected in series with saidswitching path, said series connected resistor and switching path beingshunted across said secondary winding.
 17. An arrangement as defined inclaim 2, wherein said electronic switch means has a control electrode,said control electrode being connected to operate said auxiliary switchmeans; and further including a direct current source; An input and anoutput transistor comprised by said multivibrator, the emitter of saidinput transistor being connected to one pole of said direct currentsource; a resistor connecting the collector of said input transistor tothe other pole of said direct current source; a feedback capacitorconnecting the collector of said input transistor to the base of saidoutput transistor; a resistor connecting the base of said outputtransistor to said other pole of said direct current source; a feedbackresistor connecting the base of said input transistor to the collectorof said output transistor; an emitter resistor connecting the emitter ofsaid output transistor to said one pole of said direct current source,the collector of said output transistor being connected to said otherpole of said direct current source.
 18. An arrangement as defined inclaim 17, including a resistor connected between the collector of saidoutput transistor and said other pole.
 19. An arrangement as defined inclaim 17, wherein said input and output transistors are both NPN type,the collector and emitter of both said transistors being respectivelyconnected to the positive and negative poles of said direct currentsource.
 20. An arrangement as defined in claim 13, wherein saidauxiliary switch means is a transistor of which the emitter collectorpath forms a switching path.
 21. An arrangement as defined in claim 13,wherein said auxiliary switch means comprises a switching path, saidswitching path being connected between the base of said switchingtransistor and said control winding.
 22. An arrangement as defined inclaim 14, wherein said auxiliary switch means is a thyristor and thecathode anode path thereof comprises said switching path.
 23. In anignition system for an internal combustion engine, in combination,ignition capacitor means adapted to be charged and then to be dischargedso as to produce an ignition causing spark; means for charging saidignition capacitor means; pulse operated, normally non-conductive,electronic switch means in circuit with said ignition capacitor means topermit discharge of the latter when conductive, said electronic switchmeans having a de-ionization period; pulse generator means for controlpulses in dependence on engine operation to render said electronicswitch means conductive; auxiliary switch means controlled by saidcontrol pulses for preventing charging of said ignition capacitor meansfor at least the duration of said de-ionization period of saidelectronic switch means, whereby the latter can become non-conductive inthe intervals between said control pulses; electrical timing means fordetermining the duration during which said auxiliary switch meansprevents charging of said ignition capacitor means, said timing meansbeing a monostable multivibrator, said electronic switch means having acontrol electrode, said control electrode being connected to operatesaid auxiliary switch means; a direct current source; an input and anoutput transistor comprised by said multivibrator, the emitter of saidinput transistor being connected to one pole of said direct currentsource; a resistor connecting the collector of said input transistor tothe other pole of said direct current source; a feedback capacitorconnecting the collector of said input transistor to the base of saidoutput transistor; a resistor connecting the base of said outputtransistor to said other pole of said direct current source; a feedbackresistor connecting the base of said input transistor to the collectorof said output transistor; an emitter resistor connecting the emitter ofsaid output transistor to said one pole of said direct current source,the collector of said output transistor being connected to said otherpole of said direct current source, said electronic switch means being athyristor and said pulse generator means being an engine operatedcircuit interrupter; series connected control resistor and controlcapacitor, wherein said control caPacitor and the cathode of saidthyristor are connected to the negative pole of said direct currentsource; a further input transistor of which the emitter collector pathis connected between said control resistor and the positive pole of saiddirect current source; a control transistor of which the emittercollector path is connected between the junction between said controlresistor and capacitor and the control electrode of said thyristor; atleast one diode connected non-conductively between the base of thecontrol transistor and the junction between said control resistor andsaid emitter collector path of said further input transistor; at leastone first resistor connecting the base of said input transistor to thepositive pole of said direct current source; at least one secondresistor connected in series with said circuit interrupter, said secondresistor and said circuit interrupter being connected between the baseof said further input transistor and the negative pole of said directcurrent source; a diode connecting said thyristor control electrode tothe base of said multivibrator input transistor to conduct only positivepulses to said base.
 24. In an ignition system for an internalcombustion engine, in combination, ignition capacitor means adapted tobe charged and then to be discharged so as to produce an ignitioncausing spark; means for charging said ignition capacitor means; pulseoperated, normally non-conductive, electronic switch means in circuitwith said ignition capacitor means to permit discharge of the latterwhen conductive, said electronic switch means having a deionizationperiod; pulse generator means for generating pulses in dependence onengine operation to render said electronic switch means conductive;auxiliary switch means controlled by said single control pulse forpreventing charging of said ignition capacitor means for at least theduration of said de-ionization period of said electronic switch means,whereby the latter can become non-conductive in the intervals betweensaid control pulses; electrical timing means for determining theduration during which said auxiliary switch means prevents charging ofsaid ignition capacitor means, said timing means being a mono-stablemultivibrator, said electronic switch means having a control electrode,said control electrode being connected to operate said auxiliary switchmeans; a direct current source; an input and an output transistorcomprised by said multivibrator, the emitter of said input transistorbeing connected to one pole of said direct current source; a resistorconnecting the collector of said input transistor to the other pole ofsaid direct current source; a feedback capacitor connecting thecollector of said input transistor to the base of said outputtransistor; a resistor connecting the base of said output transistor tosaid other pole of said direct current source; a feedback resistorconnecting the base of said input transistor to the collector of saidoutput transistor; an emitter resistor connecting the emitter of saidoutput transistor to said one pole of said direct current source, thecollector of said output transistor being connected to said other poleof said direct current source, said input and output transistors beingboth npn type, the collector and the emitter of both said transistorsbeing respectively connected to the positive and negative poles of saiddirect current source, said means for charging being a DC to ACconverter having a low voltage input and a high voltage output, saidinput comprising at least one primary winding and at least one controlwinding and said output having a secondary winding, and wherein saidauxiliary switch means comprises a switching path, said switching pathbeing connected in said input; and further including a common core forsaid winding; a switching transistor of which the emitter collector pathis connected in series with said primary winding across said directcurrent source; means connecting the base of said switching tranSistorto said control winding; a charging diode connecting said secondarywinding to said ignition capacitor means to form for the latter acharging current path composed of said secondary winding, chargingdiode, and ignition capacitor means; a diode non-conductively connectingthe base of said switching transistor to one pole of said direct currentsource; two series connected resistors connected across said directcurrent source, said control winding means connected to the commonjunction between said two series connected resistors, whereby the baseof said switching transistor is connected through said control windingto said common junction, and wherein said auxiliary switch means is anNPN transistor of which the collector is connected to said controlwinding, the emitter to the base of said switching transistor, and thebase to the output transistor of said multivibrator.
 25. In an ignitionsystem for an internal combustion engine, in combination, ignitioncapacitor means adapted to be charged and then to be discharged so as toproduce an ignition causing spark; means for charging said ignitioncapacitor means; pulse operated, normally non-conductive, electronicswitch means in circuit with said ignition capacitor means to permitdischarge of the latter when conductive, said electronic switch meanshaving a de-ionization period; pulse generator means for generatingpulses in dependence on engine operation to render said electronicswitch means conductive; auxiliary switch means controlled by saidpulses for preventing charging of said ignition capacitor means for atleast the duration of said de-ionization period of said electronicswitch means, whereby the latter can become non-conductive in theintervals between said pulses, said means for charging being a DC to ACconverter having an input and an output, said input comprising at leastone primary winding and at least one control winding and said outputhaving a secondary winding; a common core for said winding; a switchingtransistor of which the emitter collector path is connected in serieswith said primary winding across said direct current source; meansconnecting the base of said switching transistor to said controlwinding; a charging diode connecting said secondary winding to saidignition capacitor means to form for the latter a charging current pathcomposed of said secondary winding, charging diodes and ignitioncapacitor means, said auxiliary switching means comprising a switchingpath, and said switching path and said secondary winding being connectedin series, said auxiliary switching means being a thyristor and thecathode-anode path thereof comprising said switching path; monostablemultivibrator timing means for determining the duration during whichsaid auxiliary switch means prevents charging of said ignition capacitormeans, and wherein said electrical switch means has a control electrode,said control electrode being connected to operate said auxiliary switchmeans; and further including a direct current source; an NPN input andan NPN output transistor comprised by said multivibrator, the emitter ofsaid input transistor being connected to the negative pole of saiddirect current source; a resistor connecting the collector of said inputtransistor to the positive pole of said direct current source; afeedback capacitor connecting the collector of said input transistor tothe base of said output transistor; a resistor connecting the base ofsaid output transistor to said positive pole of said direct currentsource; a feedback resistor connecting the base of said input transistorto the collector of said output transistor; an emitter resistorconnecting the emitter of said output transistor to the negative pole ofsaid direct current source, the collector of said output transistorbeing connected to the positive pole of said direct current source; andwherein the control electrode and the cathode of said thyristor arerespectively connected to the emitter of said multivibrator outpUttransistor and to said charging diode; a diode of which the anode isconnected to the cathode of said thyristor and the cathode is connectedto the terminal of said emitter resistor remote from the emitter of saidmultivibrator output transistor.
 26. In an ignition system for aninternal combustion engine, in combination, ignition capacitor meansadapted to be charged and then to be discharged so as to produce anignition causing spark; means for charging said ignition capacitormeans; pulse operated, normally non-conductive, electronic switch meansin circuit with said ignition capacitor means to permit discharge of thelatter when conductive, said electronic switch means having ade-ionization period; pulse generator means for generating pulses independence on engine operation to render said electric switch meansconductive; auxiliary switch means controlled by said pulses forpreventing charging of said ignition capacitor means for at least theduration of said de-ionization period of said electronic switch means,whereby the latter can become non-conductive in the intervals betweensaid pulses, said means for charging being a DC to AC converter havingan input and an output, said output comprising at least one primarywinding and at least one control winding and said output having asecondary winding; a common core for said windings; a switchingtransistor of which the emitter-collector path is connected in serieswith said primary winding across said direct current source; meansconnecting the base of said switching transistor to said controlwinding; a charging diode connecting said secondary winding to saidignition capacitor means to form for the latter a charging current pathcomposed of said secondary winding, charging diode, and ignitioncapacitor means, said auxiliary switching means comprising a switchingpath, and said switching path being connected in shunt with saidsecondary winding; monostable multivibrator timing means for determiningthe duration during which said auxiliary switching means preventscharging of said ignition capacitor means, and wherein said electricalswitch means has a control electrode, said control electrode beingconnected to operate said auxiliary switch means; and further includinga direct current source; an NPN input and an NPN output transistorcomprised by said multivibrator, the emitter of said input transistorbeing connected to the negative pole of said direct current source; aresistor connecting the collector of said input transistor to thepositive pole of said direct current source; a feedback capacitorconnecting the collector of said input transistor to the base of saidoutput transistor; a resistor connecting the base of said outputtransistor to said positive pole of said direct current source; afeedback resistor connecting the base of said input resistor to thecollector of said output transistor; an emitter resistor connecting theemitter of said output transistor to the negative pole of said directcurrent source; the collector of said output transistor being connectedto the positive pole of said direct current source, and wherein saidauxiliary switch means is a thyristor and the cathode anode path thereofcomprises said switching path, one end of said secondary winding beingconnected to the anode of said charging diode, the anode of saidthyristor being connected to said one end of said secondary winding, andthe cathode of said thyristor being connected to the other end of saidsecondary winding; and further including a resistor connecting saidthyristor control electrode to said thyristor cathode; a transistor ofwhich the collector is connected to said thyristor control electrode,the base is connected to the emitter of said multivibrator outputtransistor, and the emitter is connected to the positive pole of saiddirect current source.
 27. An arrangement as defined in claim 26,including a resistor connecting the emitter of said transistor to thepositive pole of said direct current sourcE.